Just installed 3 lithium batteries. Cables do not look right.
- Thread starter BobaG
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MakeMePower
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like matt said just move the positive cable all the way to the left for connection to load, looks to be 3 minutes of work
BobaG
New Member
I would do it right now, BUT, the red cable might be a bit short and the lug bolts that came with the batteries are too short. The electrician had a hard time getting the bolt to bite when he put it in and told me not to mess with it until I get longer bolts.. So, I want to move it, but first I need to add some cable ( I have the cable) and get a longer lug bolt. Probably be a week before I can get to town and buy the bolt. We are very remote. So can I go a week like this or should I mess with it now and hope and can get the bolt to bite?
MakeMePower
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a week is fine, take your time don't break it, if you can move the black, move the black, it doesn't matter which side moves, just as long as they are on opposite sides
42OhmsPA
Who likes Electrical Gremlins?
Is this lug split or is it just a weird photo angle?
What's the white scuff marks / powdery residue from?
What's the white scuff marks / powdery residue from?
MakeMePower
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its a wing from a not amazing crimp
BobaG
New Member
42OhmsPA
Who likes Electrical Gremlins?
Zooming in more and staring at it for a few seconds I see it now.
BobaG
New Member
Good eye. Moving the black might be the trick, and mean no new cable. I knew there was a reason I posted out here. Now tell me where I can get a bolt extender.
BobaG
New Member
I know the current cabling is wrong, but can someone tell me why? Does it hurt the batteries? Not give me access to my full 300AH? Limit my peak load amps?
MakeMePower
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as shocking as it is, they don't equally share the load, thus making the one with the connections do like 20% more, shifting the cable forces them all to work more equally
3. Battery bank wiring
Sweet Tatorman
Subsistence farmer and Sweetpotato Evangelist
If those are the usual 8mm bolts, you can get various lengths in SS at a Lowes or Home Depot.Now tell me where I can get a bolt extender.
42OhmsPA
Who likes Electrical Gremlins?
Any idea on the thread pitch?
Tractor Supply, Renco / Ace, Fastenal, come to mind quickly.
I'll let others recommend the type of metal to use.
max2k
Solar Enthusiast
it would limit total capacity at full load as rightmost battery will carry most of the load and discharge first. If you move either cable to the opposite side battery it would load them more equally as the current would travel equal distances through external wires from positive terminal of each battery to its negative one.
I still see more serious problem though- no fuses between batteries. I'd check Will's videos where he tests various pre-made batteries to see if these ones have internal over-current protection. And I'd still put fuses between each battery and their common point: in case one of them fails you don't want the other two to dump their energy into the failed one starting fire. These batteries have very low internal resistance and can create insane current levels into shorts.
BobaG
New Member
Thanks, this explains it perfectly.as shocking as it is, they don't equally share the load, thus making the one with the connections do like 20% more, shifting the cable forces them all to work more equally
3. Battery bank wiring
www.victronenergy.com
BobaG
New Member
I don't know the pitch. I will contact Litime to see if they can recommend or send me some longer ones
BobaG
New Member
I will check out his video and check with LiTime to see if they have Over current protection.
wpns
Solar Joules are catch and release
Good catch, those lugs look awful. Did you see him make them up, and if so how did he make them?
Another vote for per-battery fuses.
wpns
Solar Joules are catch and release
Doesn’t matter if they have OCP, that uses semiconductors and they fail as a short.
BobaG
New Member
Here is what Litime says.
Strict Protection & Speedy Charging: LiTime LiFePO4 battery has built-in 100A BMS to protect it from overcharge, over-discharge, over-current, high temp and short circuits. Operating Temp: Charge: 0°C~50°C; Discharge: -20°C~60°C.
It does say it protects against short circuits, but I am guessing you are saying that can also fail?
max2k
Solar Enthusiast
Yeah, check out battery fires reports in 'Up in smoke' section here. The most unpleasant part is that one learns about their failure when it's needed the most as they fail 'quietly': no sparks/smoke- nothing, they just weld closed and continue to conduct no matter what.
wpns
Solar Joules are catch and release
Exactly. When the charge FETs for example fail in the ‘on’ state the first indication you may have is a fire in the future.
About bolt length. It needs to be correct. If bolt is to long, then it bottoms out and prevents correct pressure between contact surfaces.
If to short, then terminal thread gets damaged when applying tightening required for correct pressure. I'd say, measure exact bolt length required for specific terminal, and subtract 1-2mm(?) for buffer.
If not finding exact bolt length needed, get a longer and cut off to correct length. Before cutting, best would be to put on threading die, but a simple nut can also work, to bend out deformed thread at cut section. Be diligent with thread. Terminals probably aluminum and imperfections of steel thread can easily damage aluminum thread.
An other variant is to replace bolts with stud+nut. Then no need to get precise length. The slight downside here is that stud can turn while tightening the nut. Top of the stud some times have torx/hex/allen key to counter that. Also a simple stud end can be easily modified for a flat grip with wrench/spanner.
If stud+nut, diligent members here advise putting locktight into terminal, then bottom out the stud, then twist back half (?) a turn, then put the nut on and tighten to correct pressure and let the locktight cure.
If to short, then terminal thread gets damaged when applying tightening required for correct pressure. I'd say, measure exact bolt length required for specific terminal, and subtract 1-2mm(?) for buffer.
If not finding exact bolt length needed, get a longer and cut off to correct length. Before cutting, best would be to put on threading die, but a simple nut can also work, to bend out deformed thread at cut section. Be diligent with thread. Terminals probably aluminum and imperfections of steel thread can easily damage aluminum thread.
An other variant is to replace bolts with stud+nut. Then no need to get precise length. The slight downside here is that stud can turn while tightening the nut. Top of the stud some times have torx/hex/allen key to counter that. Also a simple stud end can be easily modified for a flat grip with wrench/spanner.
If stud+nut, diligent members here advise putting locktight into terminal, then bottom out the stud, then twist back half (?) a turn, then put the nut on and tighten to correct pressure and let the locktight cure.
You've received plenty of good advice about how to correct this, so no need to pile on there. My advice would be, "Find a new electrician, that knows beans about batteries." Faaaaarrrr too many tradespeople do things that will "work", at least for a while, but aren't really correct. This is a good example. It's one thing to McGyver together something to get you through a day or two - we've all had to do that on occasion. It's totally different if it's a long-term thing, and they intended to leave it like that.
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